JP2002175634A - Integrated optical member and optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated optical member and an optical pickup device that prevent a detecting optical system from being affected by the change in temperature to use. SOLUTION: The integrated optical member 20 is such that it guides the emitted light flux of a laser element to an optical disk and that it separates a required light flux among reflected light beams from the optical disk. The member 20 contains a plurality of optical surfaces inside and is characterized by forming a third diffraction grating 40 that extracts the light flux required for tracking control and focusing control from he reflected light beams on a first inclined surface 36. In addition to this integrated optical member 20, an optical pickup device using this member and an optical disk apparatus using this optical pickup device are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated optical member used for recording and reproduction of an optical disk, an optical pickup device using the integrated optical member, and an optical disk device using the optical pickup device.

[0002]

2. Description of the Related Art In conventional optical pickups, many attempts have been made to separate a light emitting light source side and a detection optical system by using many types of beam splitters. However,
As the market demand for downsizing the optical pickup has increased, attempts have been made to provide the light source and the detection optical system as an optical unit housed in the same package.

[0003] To realize this optical unit, an optical member having a diffraction grating is used. A detailed technical disclosure of this optical member is disclosed in Japanese Patent Application Laid-Open No. H10-154344. Thus, the realization of the optical member has led to a significant reduction in the size of the optical pickup, and a small optical disk device equipped with the small optical pickup has become widespread in the market.

[0004]

However, the progress of miniaturization and the spread of optical disk devices have included the following new problems. For example, the light emitting light source, the detecting element, and the optical member approach each other due to the miniaturization. Further, due to long-term use and expansion of recording applications, the light output of the light-emitting light source increases and the use temperature also increases. Furthermore, as seen in the spread of notebook PCs, the environmental temperature for housing and using in smaller housings is further increasing.

As described above, when the operating temperature range is expanded,
The effect of the coefficient of thermal expansion of each component constituting the optical unit will surface. For example, if the size and position of the optical member on which the diffraction grating is formed are affected, the causes of errors and offsets in servo control will increase.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a detection operation of a signal which is hardly affected by crosstalk without a fluctuation of a use temperature affecting a detection optical system. And an optical pickup device using the integrated optical member, and an optical disc device using the focus error detection method and the tracking error detection method. And

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from light reflected from the optical disk. An integrated optical member, wherein the integrated optical means includes a plurality of optical surfaces therein, and a diffraction grating for extracting a light beam necessary for tracking control and focus control from reflected light is formed on any of the optical surfaces. An integrated optical member, an optical pickup device using the integrated optical member, and an optical disk device using the optical pickup device.

According to the present invention, there is provided an integrated optical member capable of realizing a signal detecting operation which is hardly affected by crosstalk, without the detection optical system being affected by the fluctuation of the operating temperature by the above-mentioned structure. In addition, it is possible to provide a focus error detection method and a tracking error detection method together with an optical pickup device using the integrated optical member and an optical disk device using the optical pickup device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to the first to fifth aspects of the present invention is directed to an integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from light reflected from the optical disk. Wherein the integrated optical means includes a plurality of optical surfaces therein, and a diffraction grating for extracting a light beam required for tracking control and focus control from the reflected light is formed on one of the optical surfaces. Integrated optical member.

According to the present invention, it is possible to provide an integrated optical member in which the detection optical system is not affected by a change in the operating temperature by the above-described configuration, and a signal detection operation that is not easily affected by crosstalk can be provided. It is possible to provide an integrated optical member, an optical pickup device, and an optical disk device using the same that can be realized.

According to a sixth aspect of the present invention, a light emitting element and a light beam emitted from the light emitting element are guided to an optical disk and a required light beam is separated from light reflected from the optical disk. An optical pickup device comprising: an integrated optical member for receiving light; light receiving means for receiving light and converting the light into an electric signal; and coupling means for holding the light emitting element, the integrated optical member, and the light receiving means at mutual positions. An optical pickup device, wherein the optical member includes a plurality of optical surfaces therein, and a diffraction grating for extracting a light beam necessary for tracking control and focus control from the reflected light is formed on one of the optical surfaces. And an optical disc device using these optical pickup devices.

According to the present invention, there is provided an optical pickup device capable of realizing a signal detecting operation which is hardly affected by crosstalk without affecting a detecting optical system due to a change in a use temperature by the above-described configuration. And an optical disk device using these optical pickup devices.

According to a fourteenth aspect of the present invention, there is provided an integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from reflected light from the optical disk, Light receiving means for converting into a signal, the integrated optical member includes a plurality of optical surfaces therein, and a diffraction grating for extracting a light flux necessary for tracking control and focus control from among the reflected light is provided on one of the optical surfaces. And the diffraction grating is divided into four parts: a first arcuate region, a second arcuate region, and a first substantially D-shaped region and a second substantially D-shaped region, which are separated in the tangential direction. The light receiving means is
Two light receiving means for receiving the diffracted light in the first arcuate region;
Two light receiving means for receiving the diffracted light in the second arcuate region;
Focus error of an optical pickup device formed with three light receiving means for receiving the diffracted light in the first substantially D-shaped area and three light receiving means for receiving the diffracted light in the second substantially D-shaped area A detection method, wherein detection signals of two light receiving units that receive the diffracted light of the first arcuate region are IA and IB, respectively, and two signals arranged in reverse order of receiving the diffracted light of the second arcuate region are provided. A focus error detection method characterized by calculating a focus error signal (FA) by a relational expression of FA = {(IA + Ia) − (IB + Ib)}, where Ia and Ib are detection signals of the light receiving unit, respectively. .

According to the present invention, the drift and offset of the detection signal caused by the fluctuation of the operating temperature are canceled by the above configuration, and the focus of the optical pickup device does not affect the detecting optical system by the fluctuation of the operating temperature. An error detection method can be provided.

According to a fifteenth aspect of the present invention, there is provided an integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from light reflected from the optical disk, Light receiving means for converting into a signal, the integrated optical member includes a plurality of optical surfaces therein, and a diffraction grating for extracting a light flux necessary for tracking control and focus control from among the reflected light is provided on one of the optical surfaces. And the diffraction grating is divided into four parts: a first arcuate region, a second arcuate region, and a first substantially D-shaped region and a second substantially D-shaped region, which are separated in the tangential direction. The light receiving means is
Two light receiving means for receiving the diffracted light in the first arcuate area, two light receiving means for receiving the diffracted light in the second arcuate area, and receiving the diffracted light in the first substantially D-shaped area A tracking error detecting method for an optical pickup device, comprising: three light receiving means for detecting the diffracted light in the second substantially D-shaped region; and a first substantially D-shaped light receiving means. The detection signals of the three light receiving means for receiving the diffracted light in the region
C, IE, and IG, and the detection signals of the three light receiving units that receive the diffracted light in the second substantially D-shaped region are ID, I, and I, respectively.
F, IH, tracking error signal (TA)
TE = IC−ID−k ｛(IE + IG) − (IF + I
H) A tracking error detection method characterized in that the tracking error is calculated by a relational expression of な る (where k is a constant determined according to the operation setting).

According to the present invention, the drift of the detection signal and the offset caused by the fluctuation of the use temperature are canceled by the above configuration, and the tracking of the optical pickup device does not affect the detection optical system by the fluctuation of the use temperature. An error detection method can be provided.

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing the entire optical pickup. In FIG. 1, the whole is collectively referred to as an optical pickup 1 and has the following main components. The composite device 2 emits a light beam 3. The light beam 3 is bent by the mirror 4 and condensed by the objective lens 5 to focus on the information recording layer of the optical disk 6. The light reflected from the information recording layer is detected by the composite device 2 in the reverse order.

On the other hand, the information recording layer of the optical disk 6 has information tracks formed concentrically (more precisely, spirally). Therefore, the light beam 3 emitted from the composite element 2 is arranged so as to be in the tangential (tangential to the track) direction of the optical disk 6. The actuator 7 supports the objective lens 5 so as to be slightly displaceable. Optical disk 6
For focusing the light beam 3 on the information recording layer (focusing) and fine tracking in the track direction (tracking)
It is to do. The above-described composite element 2, mirror 4, objective lens 5, and actuator 7 are mounted on a carriage 8. Therefore, the movement beyond the tracking range is dealt with by moving the entire carriage 8 in the radius (radial) direction of the optical disc 6.

Next, the composite device 2 will be described. FIG. 2 is a perspective view showing the entire composite device. In FIG. 2, the composite element 2 has a configuration including a light source 10, an integrated optical member 20, a light receiver 60, and a coupling member 80. These components will be described in order.

First, the light source 10 has a general-purpose semiconductor laser 11 fixed to a base member 12. Since an extremely general-purpose semiconductor laser 11 can be used, the most expensive essential parts can be procured at the lowest cost, and an inexpensive optical pickup device can be provided.

Although a detailed description is omitted, the general-purpose semiconductor laser 11 naturally accommodates the laser element 13 therein and has a virtual light emitting point 19 used for geometrical optical simulation. Light emitting point 1 of laser element 13
The laser light emitted from 9 is emitted from the emission port 16 of the general-purpose semiconductor laser 11. Reference numeral 18 denotes a lead of the general-purpose semiconductor laser 11, and reference numeral 65 denotes a flexible cable for connecting to the light receiver 60.

Next, the whole of the integrated optical member 20, which is an optical member which is the subject of the present invention, will be described. FIG. 3 is an exploded perspective view of the integrated optical member 20. 3, the integrated optical member 20 includes first to fourth light guide members. As a material of each light guide member, a highly transparent resin material or optical glass is used.

The first light guide member 21 is formed in a parallel plate shape. The first light guide member 21 has a first light guide
A diffraction grating 22 is formed. This is to generate main and sub-beams (hereinafter collectively referred to as three beams) used for tracking control using the diffracted zero-order light and ± first-order light.
At this time, the pitch of the first diffraction grating 22 and the depth of the grating are:
The optimum numerical value is set according to the wavelength of the light beam and the optical power of each of the three beams. A light absorbing film 23 prevents unnecessary light such as diffuse reflection and stray light from entering the integrated optical member 20.

The second light guide member 25 is formed in a substantially triangular prism shape having a substantially right triangular cross section. Substantially right triangle slope 2
6, a second diffraction grating 27 (outgoing light extraction means) is formed in a required area. The forming process of the second diffraction grating 27 is the same as that of the first diffraction grating 22 described above. Since the light beam that has entered the second light guide member 25 from the first light guide member 21 is diffused light, it is reflected by the second diffraction grating 27 and formed on the optical power detection means 66 (see FIG. 5 described later). This is because the light is converted into convergent light. Further, the setting conditions for the grating pitch and the grating depth of the second diffraction grating 27 are the same as those of the first diffraction grating 22 described above. In particular, the second diffraction grating 27
Is set so that the + 1st-order light becomes the main component of the reflected diffracted light. More light is converged by the optical power detection means 66,
This is to increase the optical power to be detected and to ensure the accuracy of the optical power detection.

Further, the slope 26 is coated with a reciprocating path separation film 28 on the entire surface including the second diffraction grating 27. The reciprocating path separation film 28 transmits the light beam (outgoing path) incident from the first light guide member 21 substantially 100%, and conversely, reflects the light beam reflected from the optical disk 6 and returned to the second light guide member 25 ( (Return path) is reflected almost 100%.

A side surface 31 which is another surface of the second light guide member 25
The side reflection film 32 is formed in a predetermined region. This is because the diffracted light reflected by the second diffraction grating 27 is reflected again to form an image on the optical power detection means 66. In the process of forming the integrated optical member 20, the entire side surface 31 including the side reflection film 32 is coated with a light absorbing film. This is for absorbing unnecessary internal reflection, preventing stray light from entering, and protecting the reflective film coating from the influence of corrosion due to the atmosphere.

The third light guide member 35 is formed in a substantially trapezoidal column shape having a substantially trapezoidal cross section. Each side is the first slope 36
, A second inclined surface 37, a transmission surface 38, and an emission surface 39.
The first slope 36 and the second slope 37 form a parallel plane facing each other, and a third diffraction grating 40 is formed in a predetermined area of the first slope 36. The conditions for forming the third diffraction grating 40 and for setting the grating pitch and the grating depth are the same as those of the first diffraction grating 22 described above.

The third light guide member 35 is the same as the second light guide member 2 described above.
5, the return light reflected by the reciprocating path separation film 28 enters the third diffraction grating 40. Further, the third diffraction grating 40 becomes + 1st-order reflected and diffracted light to form the second light guide member 25.
However, the light is reflected by the auxiliary reflection film 30 described later on the slope 26 again, exits from the exit surface 39, and exits from the optical power detection unit 66.
Head to. At this time, the slope 26 of the second light guide member 25 corresponding to the area where the reflected diffracted light is reflected by the round-trip separation film 28
It is effective to form the auxiliary reflection film 30 (that is, between the corresponding area of the slope 26 and the round trip separation film 28). Thus, the ability of the round-trip path separation film 28 to reflect reflected diffracted light can be improved, and the level fluctuation of signal detection by the optical power detection means 66 can be suppressed.

The fourth light guide member 45 is formed in a substantially triangular prism shape having a right triangular cross section. Each surface is a slope 46, a first surface 47, and a second surface 48. The first surface 47 and the second surface 48 intersect at a right angle and serve as a reference surface of the integrated optical member 20. A light absorbing film is formed on the entire slope 46.

FIG. 4 is an overall perspective view of the light receiver 60. The OE element 63 is housed in a package 61 having an entrance 62. The signal terminal of the OE element 63 is connected to the lead terminal 64 and guided to the outside of the package 61. Furthermore, a flexible cable 65 is connected to the lead terminal 64,
Used for inspection and implementation.

FIG. 5 is a pattern diagram of the OE element 63 viewed from the entrance 62. In FIG. 5, reference numeral 66 denotes an OE element pattern corresponding to the optical power detection means. Reference numeral 67 denotes an OE element pattern corresponding to the light receiving means, which is composed of ten OE element patterns in total. It should be noted that the stippled area on the OE element pattern is the third diffraction grating 40
FIG. 4 shows a state in which diffracted light due to is incident.

Each of the light receiving means 67 includes light receiving means 67E, 67C, 67G in the optical tangential direction as an optical pickup, and light receiving means 67B at the center.
Eight OE element patterns of the light receiving means 67A, 67D, 67H are formed, and two OE element patterns of the light receiving means 67a, 67b are shifted in the radial direction at the center. The four OE element patterns in the central part are such that the disk reflected light of the main beam has a grating A41 and a grating B4.
The light is diffracted by 2 and incident. The four OE element patterns at the center are named in reverse order, and signal processing or electrical wiring described later is performed. The light receiving means 67E, 67C, and 67G make the disk reflected light of the sub beam diffracted by the grating C43 and the grating D44 to enter. Similarly, the light receiving means 67F, 67D, 67
As for H, the disk reflected light of the other sub-beams is diffracted by the grating C43 and the grating D44 to enter.

The optical power detecting means 66 has the reproduction / reflection light reflected by the side reflection film 32 provided on the second light guide member 25 described above.
The outward light in an area that does not contribute to recording forms an image. Light receiving means 6
The image of the + 1st-order reflected diffracted light reflected by the third diffraction grating 40 out of the return light described above forms an image on 7. These OE elements 6
Reference numeral 3 generates a detection current corresponding to the amount of received light, and is extracted as an electric signal with an amplifier (not shown) connected to the subsequent stage.

The relationship between the third diffraction grating 40 and ten OE element patterns of the light receiving means 67 (A to H, a, b) will be described with reference to FIG. The third diffraction grating 40 is provided with four types of grating regions. First, the third diffraction grating 40 is divided into three parts by two dividing lines parallel to the radial (radius) direction (X axis) of the optical disk 6, and is divided into an arcuate shape in the tangential (tangential line of the track: Y axis) direction. One of the isolated areas
One is lattice A41 and the other is lattice B42.
The area of the grid A41 is equal to the area of the grid B42,
The area of the entire area of the diffraction grating 40 corresponds to about ４ (the sum of the area of the grating A41 and the area of the grating B42 is about の of the entire area of the third diffraction grating 40).

The area where the reflected and diffracted light from the grating A41 forms an image is the light receiving means 67A provided at the center of the light receiving means 67.
And an image is formed on the light receiving means 67B. Further, the area where the reflected and diffracted light of the grating B42 forms an image is formed on the light receiving means 67a and 67b provided at the lower center of the light receiving means 67. That is, it becomes a main beam for focus detection. As shown in FIG. 5, the light receiving means 67A and the light receiving means 67B at the center are different from the light receiving means 67a and the light receiving means 6 at the lower center.
7b is the reverse order. Also, light receiving means 67A, B,
Blank areas provided on the left and right of a and b are the first diffraction gratings 22.
Is an area where the sub-beam generated in step (1) forms an image by the grating A41 and the grating B42. In other words, the three beams generated by the first diffraction grating 22 are reflected by the disk surface and return light 3
Only the diffracted light of the main beam out of the three returning light beams which are incident on the third diffraction grating 40 as a beam,
7A, B, a and b are imaged.

Now, when the detected current obtained by the OE conversion is represented by a symbol I, IA, IB, I
a and Ib are obtained. Therefore, the detection current can be logically configured as follows for focus detection. That is, as a focus error (hereinafter abbreviated as FE) detection logic, FE = {(IA + Ia)-(IB + Ib)} (Equation 1). The light receiving means 67A and the light receiving means 67a are
The connection can be made on the E element 63. As a result, the sum of the two light receiving means can be newly expressed as IA. Similarly, when the light receiving means 67B and the light receiving means 67b are connected, the sum of the two light receiving means can be newly expressed as IB. Therefore, by substituting into Equation 1, FE = IA-IB (Equation 2) is obtained.

The use of the FE detection logic according to Equation 2 has the following effects. Originally, the grating A41 and the grating B42 are arcuate regions of the third diffraction grating 40 that face each other in the tangential direction. Therefore, the integrated optical member 20
Suppose that thermal expansion occurs due to the heat generated by the laser element 13, since the grating A 41 and the grating B 42 are arranged apart from the center of the third diffraction grating 40, the largest change in position occurs due to the thermal expansion. Cheap. However, the light receiving means 67A, B, a, and b for receiving the diffracted lights of the grating A41 and the grating B42 are respectively arranged in reverse order to obtain the sum, and the difference of the inverted sum (crossing differential) is determined by the FE detection logic. Therefore, the drift and offset of the detection signal caused by the position change described above are canceled out by Expression 2.

The remaining divided area and the central divided area are further divided into two (that is, four divided areas) by dividing lines parallel to the tangential (tangent to the track: Y axis) direction of the optical disk 6. Lattice C43 and Lattice D
44. That is, the area of the lattice C43 and the lattice D44 is formed in a substantially D shape. In other words, the dividing line of the third diffraction grating 40 is formed in an H shape. The area of the grating C43 is equal to the area of the grating D44, and the third diffraction grating 40
Are approximately ４ of the total area of the
41 to the area of the grating D44 are the third diffraction gratings 40, respectively.
(Approximately ４ of the entire area).

By configuring the areas of the gratings A41 to D44 as described above, each of the gratings (A41 to A41 to A44) is formed.
If the power of the light beam incident on D44) is integrated over the area of each grating, each grating will receive approximately the same amount of optical power.

Similarly, the diffracted light of the three returning light beams diffracted by the grating C43 forms an image on the light receiving means 67C, 67E, and 67G provided on one side of the light receiving means 67. Similarly, the diffracted light of the three returning light beams diffracted by the grating D44 forms an image on the light receiving means 67D, 67F, and 67H provided on the other side of the light receiving means 67. These six types of light receiving areas are detected as three beams for tracking control.

Similarly to the FE detection logic described above, it is possible to logically configure the detection currents by the six types of lattice regions. That is, as a tracking error (hereinafter abbreviated as TE) detection logic, TE = IC-ID-k {(IE + IG)-(IF + IH)} (Equation 3) (where k is a constant determined according to the operation setting) ) Is obtained.

The use of the TE detection logic according to Equation 3 has the following effects. First, the light receiving means 67C,
Since 67D detects the main beam, the first and second terms of Expression 3 are normal TE detection.

Next, the third term expressed by the brackets in Expression 3 is as follows:
This means that the sum of the respective sub-beam detection currents obtained from the grating C43 and the grating D44 of the third diffraction grating 40 is obtained and differentiated. Therefore, similarly to the above-described FE detection logic, the drift and offset of the detection signal caused by the above-described position change are canceled out by Expression 3.

In particular, since the grating A41 and the grating B42 are divided into arcuate regions, the light receiving means 67A of the two-divided light receiving means is divided.
And light receiving means 67B and light receiving means 67a and light receiving means 67
It is possible to distribute the incident shape with respect to the sensor area b without waste. Similarly, since the grating C43 and the grating D44 are divided into D-shaped regions, it is possible to distribute the light from the light receiving means 67C of the independent light receiving means to the sensor area of the light receiving means 67H without waste. In addition,
Since the area from the grating A41 to the grating D44 is configured to divide the entire region of the third diffraction grating 40 into four, the third diffraction grating 40 can be easily formed.

Further, by adopting the above-described structure of dividing the area of the diffraction grating, (IA + IB) + (Ia + Ib) ≒ (IC + ID) (Equation 4) RF signal detection and each signal of FE and TE Optical power can be supplied in a well-balanced manner for detection.

The operation setting in this embodiment will be described in detail. The constant k is expressed as: k = (IC + ID) / (IE + IF + IG + IH) (Equation 5), and usually adjusts the degree of amplification at the time of OE conversion of each light receiving means so that k ≒ 1.0. . Here, as described above, the three beams formed by the first diffraction grating 22 have an optical power of the main beam of the zero-order light of 10%.
Thus, the ratio is formed such that the optical power of the sub-beams of the ± 1st order light is 1.

In order to satisfy the condition of k パ ワ ー 1.0 after substituting the ratio of the optical power into each of the light receiving means of the above equation (5), the light receiving means 67E, 67E are compared with the amplification degree of the light receiving means 67A, 67B. The amplification of 67F, 67G and 67H is about 5
Setting it to double solves it.

However, in particular, the region where the sub-beam is to be detected is easily affected by crosstalk, and TE
The signal may cause a decrease in the S / N ratio or increase the servo offset. Therefore, it is desirable that the above-mentioned five-fold amplification is adjusted without increasing as much as possible.

Therefore, in order to satisfy these conditions, 3
Modified examples of the gratings A41 to D44 utilizing the characteristics of the beam will be described. FIG. 6 is a diagram for explaining the relationship between the modified example of the grating and the OE element. In FIG. 6, reference numeral 70 denotes a third diffraction grating, which corresponds to the third diffraction grating 40 shown in FIGS. Therefore, 67 is the same as the light receiving means 67 in FIG. Lattice A71, Lattice B72, Lattice C7
3 and the grid D74 are each a grid A4 in FIG.
1 to the lattice D44. The same applies to the directions (radial direction X and tangential direction Y) of the dividing lines from the lattice A71 to the lattice 74.

The difference is that a separation grid A75 corresponding to the grid C73 is provided in the area of the grid A71. Similarly, a separation grid B76 corresponding to the grid C73 is replaced with a grid B72.
, A separation grating C77 corresponding to the grating D74 is provided in the region of the grating A71, and a separation grating D78 corresponding to the grating D74 is provided in the region of the grating B72. Then, the grating C73, the separating grating A75, and the separating grating B
76 diffracts in the same direction (in other words, the position of the same OE element), and the grating D74, the separation grating C77, and the separation grating D78 diffract in the same direction (similarly, the position of the same OE element). A separation grating D78 is formed from the respective separation gratings A75. Each of the separation gratings A75 to D78 has the same area and the same condition of the diffracted light power.

The above conditions are applied to each detection signal to verify the operation. As described above, the grating C73 and the separation grating A
Since 75 and the separation grating B76 diffract in the same direction,
The light diffracted by the main beam grating C73 enters the light receiving means 67C. At the same time, the diffracted light of the main beam by the separation gratings A75 and B76 enters the light receiving means 67C. Similarly, the diffracted light of the sub-beam of the ± 1st-order light enters the light receiving means 67E and 67G, respectively. Similarly, since the grating D74, the separation grating C77, and the separation grating D78 are diffracted in the same direction, the diffracted light of the main beam by the grating D74 is incident on the light receiving means 67D. At the same time, the diffracted light of the main beam by the separation grating C77 and the separation grating D78 enters the light receiving means 67D. Similarly, the diffracted light of the sub-beam of the ± 1st-order light enters the light receiving means 67F and 67H, respectively.

Taking the above incident conditions into consideration, Equations 1 and 2
Have no effect on the FE detection function because the areas where the separation gratings are provided are equal. The TE signal in Equation 3 does not affect the TE detection function because the first and second terms and the third term of the brackets have the same area where the separation grating is provided.

Next, Expression 4 will be verified. Since each of the separation grating A75 to the separation grating D78 corresponds to the peripheral region of the third diffraction grating 70, the influence on the main beam of the zero-order light is small, and the condition of Expression 4 is maintained almost unaffected. In Equation 5, similarly, the numerator remains almost unaffected. On the other hand, since the optical power of the sub beam of the ± 1st-order light is incident on the peripheral region of the third diffraction grating 70, in addition to the optical power of the grating C73 and the grating D74,
The optical power of the separation grating D78 is added from the separation grating A75. And the denominator increases. As a result, the light receiving means 6
The amplification of 7E, 67F, 67G and 67H can be set much lower than 5 times. Therefore, it is possible to realize a signal detection operation that is not easily affected by crosstalk.

The overall operation of the composite device 2 configured as described above will be described with reference to FIG. FIG. 7 is an explanatory diagram of the operation of the composite device 2. First, the required connection is made to the lead 18, and the laser element 13 emits the diffused light 1 from the light emitting point 19.
01 is emitted. Then, the light passes through the cover glass 17 and enters the first light guide member 21.

In the first light guide member 21, unnecessary disturbance light or light spread beyond a predetermined diffusion angle is absorbed by the light absorbing film 23, and the diffused light 10
1 is converted into three-beam outward light 102.

The outward light 102 is transmitted from the first light guide member 21 to the second light guide member 21.
The light enters the light guide member 25. The outward light 102 traveling in the second light guide member 25 reaches the slope 26. Most of the outgoing light 102 is transmitted through the reciprocating path separation film 28,
The light enters the light guide member 35. Further, the light passes through the transmission surface 38 of the third light guide member 35 and is reflected by the mirror 4 on the optical disk 6.
, And is changed to a convergent light by the objective lens 5 to be incident on the optical disk 6.

Outgoing light 1 which is diffused light that has reached the slope 26
02 outgoing light 102 in an area that does not contribute to reproduction / recording
Are incident on the second diffraction grating 27. Then, the converged light becomes the monitor reflected diffraction light 103, which travels to the side reflection film 32,
The light is reflected again, passes through the second light guide member 25 and the third light guide member 35, and exits from the exit surface 39. The monitor reflected diffraction light 103 forms an image on the optical power detection means 66 of the light receiver 60. Thus, the outgoing light 102 which is a part of the outgoing light 102 and which does not contribute to reproduction / recording is used for detecting the optical power, so that the optical power that is accurately proportional to the optical power of the laser element 13 is detected. Thus, it is possible to provide an extremely excellent front monitor system that does not affect the original reproduction / recording by the light amount.

Next, the return light 104 reflected from the recording layer of the optical disk 6 is incident on the transmission surface 38 of the third light guide member 35 through the objective lens 5 and the mirror 4 in reverse order. Return light 10
4 is reflected by the reciprocating path separation film 28 and proceeds to the third diffraction grating 40 of the third light guide member 35. Third diffraction grating 40
The return-path reflected diffracted light 105 mainly composed of the + 1st-order diffracted light
Becomes The return-path reflected diffracted light 105 is reflected again by the auxiliary reflection film 30 of the second light guide member 25,
Inject toward 0. Moreover, each grid A41
The return-path reflected diffracted light 105 reflected from the grating area of the grating D44 from the light receiving means 67A to the light receiving means 67, respectively.
H is imaged. Thus, the focus control and the tracking control can be performed by combining the detection signals from the light receiving means 67A to 67H.

[0060]

As described in detail above, according to the optical pickup device of the present invention, the optical pickup device can be constructed small and inexpensively using a general-purpose light emitting element and can be assembled with high accuracy. Thus, it is possible to provide an optical pickup device that can accurately and efficiently detect the optical power of the light emitting element.

Even if the integrated optical member undergoes thermal expansion under the influence of heat generated by the laser element, the light receiving means are arranged in the reverse order to obtain a sum, and the difference of the reverse order sum (cross differential). Is used as the FE detection logic, the drift and offset of the FE detection signal caused by the position change due to the thermal expansion are canceled out by Expression 2.
Similarly, the drift and offset of the TE detection signal caused by the above-described position change due to thermal expansion are canceled out by Expression 3.

In particular, since the grating A and the grating B are divided into arcuate regions, and the grating C and the grating D are divided into D-shaped regions, the incident shape with respect to each sensor area of the light receiving means is lightly distributed. You can also.

In addition, since the area of the grating A to the grating D is configured so that the entire area of the third diffraction grating is divided into four equal parts, the diffraction grating can be easily formed. further,
Separation gratings A and B corresponding to the grating C are provided in the regions of the gratings A and B, and separation gratings C and D corresponding to the grating D are provided in the regions of the gratings A and B, respectively. is there.

As described above, the integrated optical member capable of realizing the signal detecting operation which is hardly affected by the crosstalk without affecting the detecting optical system due to the change of the use temperature, and the integrated optical member. It is possible to provide a focus error detection method and a tracking error detection method in addition to an optical pickup device and an optical disk device using the optical pickup device.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire optical pickup.

FIG. 2 is a perspective view showing the entire composite device.

FIG. 3 is an exploded perspective view of the integrated optical member.

FIG. 4 is an overall perspective view of a light receiver.

FIG. 5 is a pattern diagram of the OE element viewed from the entrance.

FIG. 6 is a view for explaining the relationship between a modified example of the grating and the OE element.

FIG. 7 is an explanatory diagram of the operation of the composite device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical pickup 2 Composite element 3 Light beam 4 Mirror 5 Objective lens 6 Optical disk 7 Actuator 8 Carriage 10 Light source 11 General-purpose semiconductor laser 12 Base member 13 Laser element 16 Exit 17 Cover glass 18 Lead 19 Light emitting point 20 Integrated optical member 21 First Light guide member 22 First diffraction grating 23 Light absorption film 25 Second light guide member 26 Slope 27 Second diffraction grating 28 Reciprocating path separation film 29 Optical path effective area 30 Auxiliary reflection film 31 Side surface 32 Side reflection film 35 Third light guide member 36 first slope 37 second slope 38 transmission plane 39 exit plane 40, 70 third diffraction grating 41, 71 grating A 42, 72 grating B 43, 73 grating C 44, 74 grating D 45 fourth light guide member 46 slope 47 First surface 48 Second surface 60 Light receiver 61 Package 62 Entrance port 63 OE element 6 Lead terminals 65 flexible cable 66 optical power detecting means 67A~67H light receiving means 75 separating grating A 76 separation grating B 77 backward separation grating C 78 separation grating D 101 diffused light 102 outgoing light 103 monitors reflected diffraction light 104 backward light 105 reflected diffraction light

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Goto 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Eizo Ono 1006 Kadoma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. Hiroshi 1006 Kadoma, Kadoma, Osaka Prefecture F-term (reference) 2H049 AA02 AA06 AA45 AA50 AA57 AA64 AA66 5D118 AA14 CD02 CD03 CF17 CG02 DA20 DA33 DA35 DB16 DB27 5D119 AA36 EA02 EA03 JA24

Claims (15)

[Claims] An integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from reflected light from the optical disk, wherein the integrated optical means includes a plurality of optical surfaces therein. An integrated optical member, wherein a diffraction grating for extracting a light beam required for tracking control and focus control from the reflected light is formed on any of the optical surfaces. 2. The diffraction grating is divided into a central region divided into three by two division lines parallel to a radial direction of the optical disk and two arcuate regions separated in a tangential direction.
2. The integrated optical member according to claim 1, wherein the central area is further divided into a substantially D-shaped area further divided into two by a dividing line parallel to a tangential direction of the optical disc. 3. The device according to claim 2, wherein each of the two arc-shaped regions and the two substantially D-shaped regions are formed to have an area that divides the entire region of the diffraction grating into approximately four equal parts. Integrated optics. 4. The diffraction grating is formed by dividing an entire region of the diffraction grating into two arc-shaped regions and two substantially D-shaped regions by an H-shaped dividing line into approximately four equal parts. The integrated optical member according to claim 1, wherein: 5. Each of the two arcuate regions has the substantially D shape.
The integrated optical member according to any one of claims 2 to 4, wherein a separation grating that diffracts in the same direction as the character-shaped region is formed. 6. A light-emitting element, an integrated optical member for guiding a light beam emitted from the light-emitting element to an optical disk and separating a required light beam from reflected light from the optical disk, and a light-receiving element for receiving light and converting the light into an electric signal Means, and an optical pickup device having coupling means for holding the light emitting element, the integrated optical member, and the light receiving means in a mutual position, wherein the integrated optical member includes a plurality of optical surfaces therein, An optical pickup device, wherein a diffraction grating for extracting a light beam necessary for tracking control and focus control from the reflected light is formed on one of the optical surfaces. 7. The diffraction grating is divided into a central area divided into three by two dividing lines parallel to a radial direction of the optical disc and two arcuate areas separated in a tangential direction.
Further, the central area is further divided into two substantially D-shaped areas by a dividing line parallel to the tangential direction of the optical disk, and the two arc-shaped areas and the two substantially D-shaped areas are each a diffraction grating. 7. The optical pickup device according to claim 6, wherein the optical pickup device is formed in an area that divides the entire region into approximately four equal parts. 8. The diffraction grating is formed by dividing an entire area of the diffraction grating into two arc-shaped areas and two substantially D-shaped areas by an H-shaped dividing line. 7. The optical pickup device according to claim 6, wherein: 9. Each of the two arcuate regions has the substantially D shape.
9. The optical pickup device according to claim 7, wherein a separation grating diffracting in the same direction as the character-shaped region is formed. 10. A light-emitting element, an integrated optical member for guiding a light beam emitted from the light-emitting element to an optical disk and separating a required light beam from light reflected from the optical disk, and a light-receiving element for receiving light and converting the light into an electric signal Means, and an optical pickup device having coupling means for holding the light emitting element, the integrated optical member, and the light receiving means in a mutual position, wherein the integrated optical member includes a plurality of optical surfaces therein, A diffraction grating for extracting a light beam necessary for tracking control and focus control from the reflected light is formed on one of the optical surfaces, and a first arcuate region in which the diffraction grating is separated in a tangential direction and a second arcuate region. And a first substantially D-shaped region and a second substantially D-shaped region are divided into four, and the light receiving means receives the diffracted light of the first arcuate region. hand And two light receiving means for receiving the diffracted light in the second arcuate region; three light receiving means for receiving the diffracted light in the first substantially D-shaped region; An optical pickup device comprising: three of the light receiving means for receiving diffracted light in a D-shaped region. 11. The detection signals of the two light receiving means for receiving the diffracted light of the first arcuate region are respectively IA and IB, and are arranged in reverse order of receiving the diffracted light of the second arcuate region. The detection signals of the light receiving means are Ia and Ia, respectively.
11. The focus error signal (FA) is calculated by a relational expression of FA = {(IA + Ia)-(IB + Ib)} where b.
An optical pickup device as described in the above. 12. The detection signals of the three light receiving means for receiving the diffracted light in the first substantially D-shaped area are respectively represented by IC and I.
E and IG, and the detection signals of the three light receiving means for receiving the diffracted light in the second substantially D-shaped region are ID and I, respectively.
F, IH, tracking error signal (TA)
TE = IC−ID−k ｛(IE + IG) − (IF + I
The optical pickup device according to claim 10, wherein the optical pickup device is calculated by a relational expression H) Ｈ (where k is a constant determined according to an operation setting). 13. An optical disk device using the optical pickup device according to claim 6. 14. An integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from reflected light from the optical disk, and a light receiving means for receiving light and converting the light into an electric signal. The integrated optical member includes a plurality of optical surfaces therein, and forms a diffraction grating on one of the optical surfaces for extracting a light flux required for tracking control and focus control from the reflected light, and the diffraction grating The grating is divided into a first arcuate region and a second arcuate region separated in the tangential direction, a first substantially D-shaped region, and a second substantially D-shaped region. Two light receiving means for receiving the diffracted light in the first arcuate region, two light receiving means for receiving the diffracted light in the second arcuate region, and diffraction of the first substantially D-shaped region Three light receiving means for receiving light; A focus error detection method for an optical pickup device, comprising: three light receiving means for receiving the diffracted light in the second substantially D-shaped region, wherein the light receiving device receives the diffracted light in the first arcuate region. When the detection signals of the two light receiving units are IA and IB, respectively, and the detection signals of the two light receiving units arranged in reverse order to receive the diffracted light in the second arcuate region are Ia and Ib, respectively,
A focus error detection method, wherein a focus error signal (FA) is calculated by a relational expression of FA = {(IA + Ia)-(IB + Ib)}. 15. An integrated optical member for guiding a light beam emitted from a light emitting element to an optical disk and separating a required light beam from reflected light from the optical disk, and a light receiving means for receiving light and converting the light into an electric signal. The integrated optical member includes a plurality of optical surfaces therein, and forms a diffraction grating on one of the optical surfaces for extracting a light flux required for tracking control and focus control from the reflected light, and the diffraction grating The grating is divided into a first arcuate region and a second arcuate region separated in the tangential direction, a first substantially D-shaped region, and a second substantially D-shaped region. Two light receiving means for receiving the diffracted light in the first arcuate area, two light receiving means for receiving the diffracted light in the second arcuate area, and diffraction of the first substantially D-shaped area Three light receiving means for receiving light; A tracking error detecting method for an optical pickup device, comprising: three light receiving means for receiving the diffracted light in the second substantially D-shaped region; The detection signals of the three light receiving means for receiving light are respectively IC, IE and IG,
When the detection signals of the three light receiving units that receive the diffracted light in the second substantially D-shaped region are ID, IF, and IH, respectively, the tracking error signal (TA) is expressed as TE = IC-ID-k ｛(IE + IG)-(IF + I
H) ト ラ ッ キ ン グ (where k is a constant determined in accordance with the operation setting).